"Ra's al Ghul is the Big Bad that just won't go away. 'Arrow' alum Matt Nable is set to reprise his role as the onetime League of Assassins leader on DC's 'Legends of Tomorrow,' TVLine has confirmed. Ra's was killed at the end of Season 3, but given that the 'Arrow/Flash' offshoot heavily features time travel, that piddly fact hardly seems like a death sentence."

"When heroes alone are not enough... the world needs legends. Having seen the future, one he will desperately try to prevent from happening, time-traveling rogue Rip Hunter is tasked with assembling a disparate group of both heroes and villains to confront an unstoppable threat - one in which not only is the planet at stake, but all of time itself. Can this ragtag team defeat an immortal threat unlike anything they have ever known?"